package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.hmdp.dto.Result;
import com.hmdp.dto.UserDTO;
import com.hmdp.entity.Follow;
import com.hmdp.mapper.FollowMapper;
import com.hmdp.service.IFollowService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.service.IUserService;
import com.hmdp.utils.RedisConstants;
import com.hmdp.utils.UserHolder;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;
import java.util.Collections;
import java.util.List;
import java.util.Set;
import java.util.stream.Collectors;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class FollowServiceImpl extends ServiceImpl<FollowMapper, Follow> implements IFollowService {
    @Resource
    StringRedisTemplate stringRedisTemplate;

    @Resource
    IUserService userService;

    @Override
    public Result follow(Long followUserId, Boolean isFollow) {
        Long userId = UserHolder.getUser().getId();
        // 自己关注的人
        String key = RedisConstants.FOLLOW_KEY + userId;
        // 通过传入的布尔值判断
        if(isFollow) {
            Follow follow = new Follow();
            follow.setUserId(userId);
            follow.setFollowUserId(followUserId);
            this.save(follow);
            stringRedisTemplate.opsForSet().add(key, followUserId.toString());
        }else {
            this.remove(new LambdaQueryWrapper<Follow>()
                .eq(Follow::getUserId, userId)
                .eq(Follow::getFollowUserId, followUserId)
            );
            stringRedisTemplate.opsForSet().remove(key, followUserId.toString());
        }
        return Result.ok("成功");
    }

    @Override
    public Result isFollow(Long followUserId) {
        Long userId = UserHolder.getUser().getId();
        LambdaQueryWrapper<Follow> wrapper = new LambdaQueryWrapper<Follow>()
            .eq(Follow::getUserId, userId)
            .eq(Follow::getFollowUserId, followUserId);
        int count = this.count(wrapper);
        return Result.ok(count > 0);
    }

    @Override
    public Result commonFollow(Long targetId) {
        // 找到自己关注的
        Long userId = UserHolder.getUserId();
        String key1 = RedisConstants.FOLLOW_KEY + userId;
        // 找到他关注的
        String key2 = RedisConstants.FOLLOW_KEY + targetId;
        // 求交集
        Set<String> intersect = stringRedisTemplate.opsForSet().intersect(key1, key2);
        // 无交集
        if(intersect == null || intersect.isEmpty())  {
            return Result.ok(Collections.emptyList());
        }
        // 有交集，返回DTO格式
        List<Long> ids = intersect.stream().map(Long::valueOf).collect(Collectors.toList());
        List<UserDTO> users = userService.listByIds(ids).stream()
            .map(user -> BeanUtil.copyProperties(user, UserDTO.class) ).collect(Collectors.toList());

        return Result.ok(users);
    }
}
